• Imaging Science in Dentistry
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• v.39 no.2
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• pp.89-92
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• 2009

Purpose: To assess the angle between mandibular canal and occlusal plane at each posterior tooth region and location of mental foramen on the panoramic radiographs. Materials and Methods: This study analysed 46 half-mandibles of panoramic radiographs. Inferior border of mandibular canal was traced. Occlusal plane was drawn from lingual cusp tip of the first premolar to distolingual cusp tip of the second molar. Perpendicular line from occlusal plane was drawn at each tooth region and then tangential lines were drawn from the crossing points at canal. the angle between occlusal plane and tangential line was measured. The location of mental foramen was also studied. According to the location of mental foramen, radiographs were divided into M (mesial) group and D (distal) group on the basis of the second premolar. and then inter-group analysis about mandibular canal angle was done. Results: The angles of mandibular canals were -17.7$^{\circ}$, -9.5$^{\circ}$, 8.2$^{\circ}$, 22.3$^{\circ}$, and 39.2$^{\circ}$at first premolar, second premolar, first molar, second molar, and third molar, respectively. The commonest position of the mental foramen was distal to the second premolar. Inter-group comparison showed statistically significant difference at the second premolar and the first molar(p<0.001). Conclusion: The knowledge of mandibular canal angle and location of mental foramen can help understanding the course of mandibular canal. (Korean J Oral Maxillofac Radiol 2009; 39: 89-92)

• Imaging Science in Dentistry
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• v.52 no.3
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• pp.319-326
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• 2022

This report presents the case of a 5-year-old boy with a hard swelling on the right side of the mandible body. An important point of this case is that the primary imaging finding was fine spicules in the inferior border of the mandible on panoramic radiography without significant changes in bone density. Cone-beam computed tomography views revealed a lytic lesion on the lingual side of the right mandibular body with the destruction of the lingual cortex and periosteal reaction from the midline to the first molar area. Careful attention to this radiographic finding in the primary stage in the absence of other significant imaging findings, particularly in children, could result in the early diagnosis of desmoplastic fibroma. Therefore, a better prognosis can be expected following early surgical treatment.

• Korean Journal of Radiology
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• v.1 no.1
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• pp.33-37
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• 2000

Objective: To describe the radiologic findings of migrating lobar atelectasis of the right lung. Materials and Methods: Chest radiographs (n = 6) and CT scans (n = 5) of six patients with migrating lobar atelectasis of the right lung were analyzed retrospectively. The underlying diseases associated with lobar atelectasis were bronchogenic carcinoma (n = 4), bronchial tuberculosis (n = 1), and tracheobronchial amyloidosis (n = 1). Results: Atelectasis involved the right upper lobe (RUL) (n = 3) and both the RUL and right middle lobe (RML) (n = 3). On supine anteroposterior radiographs (n = 5) and on an erect posteroanterior radiograph (n = 1), the atelectatic lobe(s) occupied the right upper lung zone, with a wedge shape abutting onto the right mediastinal border. On erect posteroanterior radiographs (n = 6), the heavy atelectatic lobe(s) migrated downward, forming a peri- or infrahilar area of increased opacity and obscuring the right cardiac margin. Erect lateral radiographs (n = 4) showed inferior shift of the anterosuperiorly located atelectatic lobe(s) to the anteroinferior portion of the hemithorax. Conclusion: Atelectatic lobe(s) can move within the hemithorax according to changes in a patient s position. This process involves the RUL or both the RUL and RML.

• Radiation Oncology Journal
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• v.21 no.3
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• pp.183-191
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• 2003

Purpose: To suggest the optimal radiation fields after a surgical resection based on a nationwide survey on the principles of radiotherapy for rectal cancer in the Korean Patterns on Care Study. Materials and method: A consensus committee, composed of radiation oncologists from 18 hospitals in Seoul Metropolitan area, developed a survey format to analyze radiation oncologist's treatment principles for rectal cancer after a surgical resection. The survey format included 19 questions on the principles of defining field margins, and was sent to the radiation oncologists in charge of gastrointestinal malignancies in all korean hospitals (48 hospitals). Thirty three ($69\%$) oncologists replied. On the basis of the replies and literature review, the committee developed guidelines for the optimal radiation fields nor rectal cancer Results: The following guidelines were developed: superior border between the lower tip on the L5 vertebral body and upper sacroiliac joint; inferior border $2\~3$ cm distal to the anastomosis in patient whose sphincter was saved, and $2\~3$ cm distal to the perineal scar In patients whose anal sphincter was sacrificed; anterior margin at the posterior lip of the symphysis pubis or $2\~3$ cm anterior to the vertebral body, to include the internal iliac lymph node and posterior margin $1.5\~2$ cm posterior to the anterior surface of the surface, to include the presacral space with enough margin. Comparison with the guidelines, the replies on the superior margin coincided in 23 cases ($70\%$), the inferior margin after sphincter saving surgery in 13 ($39\%$), the inferior margin after adbominoperineal resection in 32 ($97\%$), the lateral margin in 32 ($97\%$), the posterior margins in 32 ($97\%$) and the anterior margin in 16 ($45\%$). Conclusion: These recommendations should be tailored to each patient according to the clinical characteristics such as tumor location, pathological and operative findings, for the optimal treatment. The adequacy of these guidelines should be proved be following the Korean Patterns of Care Study.

• Journal of Periodontal and Implant Science
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• v.32 no.2
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• pp.379-388
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• 2002

For the success of dental implant, accurate radiographic evaluation is prerequisite for planning the location of the osseointegrated implants and avoiding injury to vital structures. CT/MPR(computed tomography/multiplanar reformation) shows improved visualization of inferior alveolar canal. In order to obtain cross-sectional images parallel to the teeth, the occlusal plane is used to orientate for the axial plane. If the direction of axial plane is not parallel to the occlusal plane, the reformatted cross-sectional scans will be oblique to the planned fixture direction and will not show the actual dimension of the planned fixture's location. If the available bone height which measured in the cross-sectional view is much greater than the actual available bone height, penetration of canal may occur. The aim of this study is to assess the effect of the axial plane to measurement of available bone height for dental implant in computed tomography of the mandible. 40 patients who had made radiographic stents and had taken CT were selected. The sites that were included in the study were 45 molar regions. In the central panoramic scan, the length from alveolar crest to superior border of inferior alveolar canal(available bone height, ABH) was measured in direction of reformatted cross-sectional plane(uncorrected ABH). Then, length from alveolar crest to superior border of canal was measured in direction of stent(corrected ABH). The angle between uncorrected ABH and corrected ABH was measured. From each ABH, available fixture length was decided by $Br{{\aa}}nemark$ system. The results were following ; the difference between two ABHs was statistically significant in both first and second molar(p< 0.01). The percentage of difference more than 1 mm was 8.7% in first molar and 15.5% in second molar. The percentage of difference more than 2 mm was 2.0% in first molar and 6.6% in second molar. The maximum value of difference was 2.5 mm in first molar and 2.2 mm in second molar. The correlations between difference of 2 ABHs and angle was positive correlations in both first and second molar. The correlation coefficient was 0.534 in first molar and 0.728 in second molar. The second molar has a stronger positive correlation. The percentage of disagreement between 2 fixture lengths from two ABHs was 24.4% in first molar and 28.9% in second molar.

• Radiation Oncology Journal
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• v.28 no.4
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• pp.231-237
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• 2010

Purpose: We investigated the effect of location changes in the inferior border of the belly board (BB) aperture by adding a bladder compression device (BCD). Materials and Methods: We respectively reviewed data from 10 rectal cancer patients with a median age 64 years (range, 45~75) and who underwent computed tomography (CT) simulation with the use of BB to receive pelvic radiotherapy between May and September 2010. A CT simulation was again performed with the addition of BCD since small bowel (SB) within the irradiated volume limited boost irradiation of 5.4 Gy using the cone down technique after 45 Gy. The addition of BCD made the inferior border of BB move from symphysis pubis to the lumbosacral junction (LSJ). Results: Following the addition of BCD, the irradiated volumes of SB and the abdominopelvic cavity (APC) significantly decreased ($174.3{\pm}89.5mL$ vs. $373.3{\pm}145.0mL$, p=0.001, $1282.6{\pm}218.7mL$ vs. $1,571.9{\pm}158mL$, p<0.001, respectively). Bladder volume within the treated volume increased with BCD ($222.9{\pm}117.9mL$ vs. $153.7{\pm}95.5mL$, p<0.001). The ratio of irradiated bladder volume to APC volume with BCD ($33.5{\pm}14.7%$) increased considerably compared to patients without a BCD ($27.5{\pm}13.1%$) (p<0.001), and the ratio of irradiated SB to APC volume decreased significantly with BCD ($13.9{\pm}7.6%$ vs. $24.2{\pm}10.2%$, p<0.001). The ratios of the irradiated SB volume and irradiated bladder volume to APC volume negatively correlated (p=0.001). Conclusion: This study demonstrated that the addition of BCD, which made the inferior border of BB move up to the LSJ, increased the ratio of the bladder to APC volume and as a result, decreased the irradiated volume of SB.

• Journal of Korean Foot and Ankle Society
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• v.2 no.2
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• pp.88-92
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• 1998

The course of the sural nerve in the calf has been well documented, but there is a general lack of information concerning the distal course of the nerve. The purpose of this study was to describe the distal course of the sural nerve and its surgical implications. Seven fresh amputated specimens were dissected to show the anatomy of the sural nerve in the foot and ankle. At the level of about 10cm proximal to the plantar surface, the sural nerve coursed anteriorly and inferiorly away from the Achilles tendon. 2 to 4 lateral calcaneal branches arose. The first branch of the lateral calcaneal branches coursed along the lateral border of the Achilles tendon, and it arose at 8cm proximal to the plantar surface in 2 specimens, 12cm proximal to the plantar surface in 4 specimens, and at 12cm proximal to the plantar surface in one specimen. The main nerve trunk continued distally plantar to the peroneal tendons and divided into two terminal branches and crossed peroneus longus tendon at the level of the inferior border of the calcaneo-cuboid joint, at about 3cm(range, $2.5\sim3.0$)cm from the plantar surface. In conclusion, a longitudinal incision lateral to the Achilles tendon would cross the path of the sural nerve at about 10cm proximal to the plantar surface. When the first branch of them arise more than 10cm above the plantar surface, a logitudinal incision lateral to the Achilles tendon may be made without damage. The other lateral calcaneal branches will be cut when we make transverse incision paralled to the plantar surface. The terminal branch also may be in danger by the same transverse incision.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.28 no.3
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• pp.196-204
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• 2002

For the study of its stability when the screw has been fixed after sagittal split ramus osteotomy(SSRO) of the mandible, the methods of screw arrangement are classified into two types, triangular and straight. The angles of screws to the bone surface are classified as perpendicular arrangements, the $60^{\circ}$ anterioinferior screw, known as triangular, and the most posterior screw, called straight arrangement, thus there are four types. The finite element method model has been made by using a three dimensional calculator and a supercomputer. The load directions are to the anterior teeth, premolar region, and molar region, and the bite force is 1 Kgf to each region. The distribution of stress, the von-Mises yield strength, and safety of margin refer to the total sum of transformed energy have been studied by comparison with each other. The following conclusion has been researched : 1. When shear stress is compared, in the triangular arrangement in the form of "ㄱ", the anterosuperior screw is seen at contributing to the support of the bone fragment. In the straight arrangement, substantial stress is seen to be concentrated on the most posterior angled screw. 2. When the von-Mises yield strength is compared, it seemed that the stress concentration on the angled anteroinferior screw is higher, it shows a higher possibility of fracture than any other screw. In the straight arrangement, stress appeared to be concentrated on the most posteriorly angled screw. 3. When the safety margins of the transfomed energy are compared, the energy conduction is much greater in the case of the angled screw than in the case of the perpendicular screw. The triangular arrangement in the form of "ㄱ" shows a superior clinical sign to that of the straight arrangement. Judging from the above results, when the screw fixation is made after SSRO in practical clinical cases, two screws should be inserted in the superior border of mandibular ramus and a third screw of mandibular inferior border should be inserted in the form of triangular. All screws on the bony surface should be placed perpendicularly-$90^{\circ}$ angles apparently best promote bony support and stability.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.28 no.2
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• pp.126-131
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• 2002

Anatomical shape of the mandibular ramus, which includes the area from the rear of the mandibular second molar to the mandibular posterior border and from the mandibular sigmoid notch to the inferior mandibular border, must be carefully considered to perform orthognathic surgery. The locations of the lingula and mandibular foramen in medial side of mandibular ramus are one of the most important factors to decide the location of the horizontal medial osteotomy in sagittal split ramus osteotomy and to select the line of vertical osteotomy in intraoral vertical ramus osteotomy. Sixty-five different Korean human dry mandibles were surveyed. All mandible have permanent dentition including complete eruption of the mandibular second molar. The locations of the lingula and mandibular foramen in medial side of the ramus were identified and following results were obtained. Anterior ramal horizontal distance from lingula was $16.13{\pm}3.53mm(range:8.6{\sim}24.3mm)$, anterior ramal horizontal distance from mandibular foramen was $23.91{\pm}4.79mm(range: 14.1{\sim}39.7mm)$, horizontal width of mandibular foramen was $2.79{\pm}0.95mm(range:1.5{\sim}6.1mm)$, height of lingula was $10.51{\pm}3.84mm(range:3.1{\sim}22.4mm)$, vertical distance from sigmoid notch to lingula was $19.82{\pm}5.11mm(range:9.1{\sim}35.3mm)$. From this study, the result could be used to select the location of osteotomy lines and to decide amount of periosteal elevation to avoid injury of neurovascular bundle, and to accomplish the appropriate split in Korean patients in mandibular orthognathic surgery.

• Journal of the korean academy of Pediatric Dentistry
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• v.38 no.4
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• pp.368-375
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• 2011

The aim of this study was to evaluate the position of the mandibular foramen in panoramic radiographs of Korean children to provide information for successful inferior alveolar nerve block anesthesia. 240 panoramic radiographs of 7 to 15-year-old boys and girls were analyzed. The subjects were divided into 4 groups in boys and girls according to their age.; 7-8, 9-10, 11-12 and 13-15 years old. The shortest distances from the center of the mandibular foramen to the anterior border of ramus, to the posterior border of ramus, to the antegonial notch and to the mandibular notch and the perpendicular distances from the center of the mandibular foramen to the occlusal plane were measured. The following results were obtained. 1) Although the relative position of the mandibular foramen in the ramus of mandible tended to move anteriorly for both genders with age, the vertical position did not correlate with age. 2) The mandibular foramen moved upward in relation to the occlusal plane with age, and showed statistically significant correlation with age(p<0.05). 3) The mandibular foramina of boys, when compared to those of girls, were located more superiorly in relation to the occlusal plane and more superiorly and posteriorly in the ramus of mandible.